The present invention relates to the recovery of metals and/or oxides thereof and more particularly relates to the recovery of metals and/or oxides thereof from such sources as ore and mill tailings and the like. Even more particularly, the present invention relates to the recovery of such metals as tantalum and/or niobium and/or oxides thereof.
Many metals and/or oxides thereof are recovered from such sources as ore wherein a variety of different separation techniques are used. For instance, with respect to tantalum, tantalum and/or oxides thereof are typically recovered from mining operations wherein the tantalum and/or oxide thereof is present as an ore. The ore is typically reduced to a small aggregate or particle size such as about 200 microns or less. This reduction in size can be accomplished, for instance, using ball milling or other reduction steps. After the reduction of the ore to a small particle size, gravity separation techniques can be used to recover tantalum wherein, due to the density of tantalum and/or oxide thereof, the tantalum and/or oxide thereof will settle prior to other minerals present in the ore and thus recovery of a large percentage of the tantalum and/or oxide thereof is possible. However, a percentage of the tantalum and/or oxide thereof that is present in the ore will typically be reduced to a very small particle size such as below about 10 microns which prevents the separation of this form of tantalum and/or oxide thereof by gravity techniques. Typically, in separation operations, this tantalum and/or oxide thereof will simply be discarded as tailings and therefore remain unrecoverable which is a significant economic loss to the mining operations.
While flotation is a technique that can possibly be used in the recovery of metals and/or oxides thereof, the flotation technique with respect to the recovery of metals and/or oxides thereof such as tantalum and/or oxides thereof has been unsuccessful in previous attempts because either a very small percentage of the tantalum and/or oxide thereof is recovered by flotation or the recovery is interfered with by the presence of other unwanted impurities such as other metallic impurities, such as iron. Accordingly, the use of flotation for the recovery of fine size fractions of metals and/or oxides thereof, such as tantalum and/or oxide thereof, has generally been unsuccessful.
There is a need in the industry for processes to permit the total recovery of or the near total recovery of all tantalum and/or oxide thereof present in ore or other sources including the very fine size fractions of tantalum and/or oxide thereof found in ore as well as other sources.